The isolation and purification of the human enzyme, dopamine-beta-hydroxylase (DBH), is in progress. Conventional methods of purification have yielded a 300-500 fold purification. Limited stability and marginal recovery of active enzyme are problems that msut be overcome in order to obtain sufficient amounts of purified enzyme to proceed with physiochemical and kinetic characterizations. Clinical studies have been conducted on patients with renal failure and subjects with primary hypertension. We have further characterized an autonomic defect in chronic uremia. We have also performed a study which attests to the efficacy of psychotherapeutic control of hypertension and indicates that alterations of DBH in plasma reflect adrenergic activity. These studies are being extended.